Terahertz plasmonics for testing very large-scale integrated circuits under bias

ABSTRACT

Various embodiments are described that relate to failure determination for an integrated circuit. An integrated circuit can be tested to determine if the integrated circuit is functioning properly. The integrated circuit can be subjected to a specific radiation such that the integrated circuit produces a response. This response can be compared against an expected response to determine if the response matches the expected response. If the response does not match the expected response, then the integrated circuit fails the test. If the response matches the expected response, then the integrated circuit passes the test.

GOVERNMENT INTEREST

The innovation described herein may be manufactured, used, imported,sold, and licensed by or for the Government of the United States ofAmerica without the payment of any royalty thereon or therefor.

BACKGROUND

An electrical system can comprise various electrical hardwarecomponents, such as transistors. As more electrical hardware componentsare added to the electrical system, it can be beneficial to have theelectrical system incorporated into a substrate as an integratedcircuit. The integrated circuit can be used in a variety ofapplications, such as personal computers and communications equipment.

SUMMARY

In one embodiment, a system, comprises an emission component and areception component. The emission component can be configured to causean emission of a radiation set upon an integrated circuit such that theintegrated circuit produces a response. The reception component can beconfigured to receive the response. The response, in view of theradiation set, can indicate a failure state of the integrated circuit.The emission component, the reception component, or a combinationthereof can be, at least in part, non-software.

In another embodiment, a system comprises an analysis component and adetermination component. The analysis component can be configured toperform an analysis on a response produced by an emission of a radiationupon an integrated circuit. The determination component can beconfigured to determine a health of the integrated circuit based, atleast in part, on a result of the analysis. The report can be outputtedthat indicates the health. The analysis component, the determinationcomponent, or a combination thereof can be implemented, at least inpart, by way of hardware

In yet another embodiment, a method can comprise recognizing, by way ofa failure test apparatus, a failure of an integrated circuit. The methodcan additionally comprise determining a radiation frequency subjectedupon the integrated circuit. The method can also comprise determining aresponse voltage of the integrated circuit that is in response to beingsubjected to the radiation frequency. In addition, the method cancomprise propagating an information set onto a database. The informationset can reflect the radiation frequency, the response voltage, and thefailure.

BRIEF DESCRIPTION OF THE DRAWINGS

Incorporated herein are drawings that constitute a part of thespecification and illustrate embodiments of the detailed description.The detailed description will now be described further with reference tothe accompanying drawings as follows:

FIG. 1 illustrates one embodiment of an environment with a systemcomprising an emission component and a reception component;

FIG. 2 illustrates one embodiment of an environment with a systemcomprising the emission component, the reception component, a selectioncomponent, and an evaluation component;

FIG. 3 illustrates one embodiment of a system comprising an analysiscomponent and a determination component;

FIG. 4 illustrates one embodiment of a system comprising the analysiscomponent, the determination component, and an identification component;

FIG. 5 illustrates one embodiment of a system comprising a processor anda computer-readable medium;

FIG. 6 illustrates one embodiment of a method comprising three actions;

FIG. 7 illustrates one embodiment of the action illustrated as a methodcomprising three actions;

FIG. 8 illustrates one embodiment of a method comprising six actions;

FIG. 9 illustrates one embodiment of a method comprising six actions;and

FIGS. 10A-10E illustrate one embodiment of a testing environment andfour graphs.

DETAILED DESCRIPTION

Field effect transistors (FETs) can be used as efficient detectors ofTerahertz (THz) radiation. In these detectors, non-linearities in thepropagation of plasma waves in the two-dimensional electronic fluid ofthe FET channels produce a direct current voltage from the THzradiation. Such plasmonic detectors could operate at frequencies muchhigher than their cut-off frequency or maximum frequency ofoscillations. FETs operating in the plasmonic regimes can be used as THzdetectors, mixers, phase shifters and frequency multipliers at THz. Theplasmonic FET detectors can be advantageous because they can detectsingle THz pulses with enhanced responsivity and can be compatible withintegrated circuit technologies, including Si CMOS.

Non-linearities of the electron plasma in FET channels can be used totest integrated circuits, such as a Monolithic Microwave IntegratedCircuit (MMIC). Multiple non-linearities in plasma propagation canexist, such as a non-linearity that is proportional to the derivative ofthe velocity of the electrons and a non-linearity is proportional to aderivative of the current (e.g., velocity times density), as such, lowfrequencies may not produce a detectable response in at least somecircumstances. In addition, to achieve a desirable collective (plasma)oscillation, the signal can be significantly slower than theelectron-electron scattering. For the electron plasmas that are typicalin VLSI transistor channels, these non-linerities are can be probed withradiation in the THz range. The response of these non-linearities isdependent on the density of the electron plasma within the channel aswell as the electrical boundary conditions and parasitic aspects of thetransistor, making the response sensitive to many of the parameters thatare important for proper transistor operation. A THz overdampedplasmonic response can be used to detect faults in Si CMOS. Thepolarization dependence of the terahertz response can also be used toincrease the effectiveness of this technique. The advantage of thisapproach to testing MMICs and VLSIs is that the transistors can betested unbiased (so there is no need to connect them to the sources) orbiased and several transistors within the circuit and the entire circuitcan be tested.

Increasing complexity and decreasing feature size of integrated circuitsbrings to the forefront the issues of non-destructive comprehensive andubiquitous testing. THz imaging can be used for testing Very Large ScaleIntegration (VLSI), but the image quality is limited by the diffractionlimit on the order of tens or even hundreds of microns because of arelatively long wavelength of the sub-THz and THz radiation. Using thelaser terahertz emission microscopy for testing VLSI, the resolutioncould be improved to approximately 3 microns, which still might not begood enough for modern VLSI with feature sizes as small as 7 nm. F

Field effect transistors (FETs) can be used as efficient detectors ofthe THz radiation using the excitation of propagating or overdampedplasma waves in the two-dimensional electronic fluid in the FETchannels. Such plasmonic detectors could operate at frequencies muchhigher than their cut-off frequency or maximum frequency ofoscillations. FETs operating in the plasmonic regimes can also be usedas THz detectors, mixers, phase shifters and frequency multipliers atTHz. The plasmonic FET detectors have advantages over Schottky diodedetectors, such as by detecting single THz pulses with enhancedresponsivity and being compatible with integrated circuit technologies,including a silicon (Si) Complementary metal-oxide semiconductor (CMOS).A THz overdamped plasmonic response can be used to detect faults in SiCMOS. Polarization dependence can be added as a part of the terahertzresponse and can be used to testing a MMIC. The advantage of thisapproach to testing MMICs and VLSIs is that the transistors can betested unbiased (e.g., so there is no need to connect them to thesources) or biased and several transistors within the circuit and theentire circuit can be tested.

In one embodiment, a product manufacturer can obtain pre-fabricatedintegrated circuits from an outside party. In one example, a medicalmanufacturer can obtain an integrated circuit from a chip manufacturer.The medical manufacturer can incorporate the integrated circuit into amedical device, such as a monitor, a defibrillator, or a breathingmachine. The medical device can be complex and, in turn, the integratedcircuit can be complex with a vast number of transistors and otherelectrical hardware components.

With the integrated circuit being incorporated in the medical device,failure of the integrated circuit could be catastrophic. In one example,if the integrated circuit is incorporated in the defibrillator and theintegrated circuit fails, then the defibrillator could fail to functionand a patient may die. Since the medical manufacturer is notmanufacturing the integrated circuit, the medical manufacturer shouldplace in a control mechanism to determine if the integrated circuit isproperly functioning before integration.

The control mechanism can subject the integrated circuit to a radiationat a specific frequency. When functioning properly, the integratedcircuit can have an anticipated response to the specific radiationfrequency. When subjecting the integrated circuit to the specificradiation frequency an actual response can be measured. Comparing theactual response against the anticipated response can result indetermining if the integrated circuit is properly functioning orfailing. If the actual response matches the anticipated response, suchas within a tolerance, then the integrated circuit can be considered tobe properly functioning and can be used by the medical device. If theactual response does not match the anticipated response, then theintegrated circuit can be considered to be failing and can be discarded.

The following includes definitions of selected terms employed herein.The definitions include various examples. The examples are not intendedto be limiting.

“One embodiment”, “an embodiment”, “one example”, “an example”, and soon, indicate that the embodiment(s) or example(s) can include aparticular feature, structure, characteristic, property, or element, butthat not every embodiment or example necessarily includes thatparticular feature, structure, characteristic, property, or element.Furthermore, repeated use of the phrase “in one embodiment” may or maynot refer to the same embodiment.

“Computer-readable medium”, as used herein, refers to a medium thatstores signals, instructions and/or data. Examples of acomputer-readable medium include, but are not limited to, non-volatilemedia and volatile media. Non-volatile media may include, for example,optical disks, magnetic disks, and so on. Volatile media may include,for example, semiconductor memories, dynamic memory, and so on. Commonforms of a computer-readable medium may include, but are not limited to,a floppy disk, a flexible disk, a hard disk, a magnetic tape, othermagnetic medium, other optical medium, a Random Access Memory (RAM), aRead-Only Memory (ROM), a memory chip or card, a memory stick, and othermedia from which a computer, a processor or other electronic device canread. In one embodiment, the computer-readable medium is anon-transitory computer-readable medium.

“Component”, as used herein, includes but is not limited to hardware,firmware, software stored on a computer-readable medium or in executionon a machine, and/or combinations of each to perform a function(s) or anaction(s), and/or to cause a function or action from another component,method, and/or system. Component may include a software controlledmicroprocessor, a discrete component, an analog circuit, a digitalcircuit, a programmed logic device, a memory device containinginstructions, and so on. Where multiple components are described, it maybe possible to incorporate the multiple components into one physicalcomponent or conversely, where a single component is described, it maybe possible to distribute that single component between multiplecomponents.

“Software”, as used herein, includes but is not limited to, one or moreexecutable instructions stored on a computer-readable medium that causea computer, processor, or other electronic device to perform functions,actions and/or behave in a desired manner. The instructions may beembodied in various forms including routines, algorithms, modules,methods, threads, and/or programs, including separate applications orcode from dynamically linked libraries.

“Frequency”, when referring to the frequency of terahertz emission, thefrequency can refer to part of an electro-magnetic emission thatcontributes to a measured response (e.g., a significant amount of themeasured response).

FIG. 1 illustrates one embodiment of an environment 100 with a systemcomprising an emission component 110 and a reception component 120. Theemission component 110 can be configured to cause an emission of aradiation set 130 upon an integrated circuit 140 such that theintegrated circuit produces a response 150. The reception component 120can be configured to receive the response. The response 150, in view ofthe radiation set 130, can indicate a failure state of the integratedcircuit 140.

The response 150 can be considered a measurement from the radiation set130. In one example, the measurement is done under a predeterminedseries of bias voltages of the integrated circuit 140. In one example,the measurement is done under a predetermined series of the modulatedintegrated circuit bias voltages and the response 150 compared with theetalon as functions of the modulation frequencies for a comparisonresult. The response 150 can be used in a number of manners. In oneexample, the response 150 is used to determine a manufacturer of theintegrated circuit 140.

The response 150 can be transmitted to a data processing unit (e.g.,wirelessly transmitted to the data processing unit). The data processingunit can process the response 150 in accordance with big data processingtechniques.

The emission of the radiation set 150 can be composed of a narrow bandof frequencies around a center frequency, such as a narrow band producedby a THz laser, or can be a broad band of frequencies around a centerfrequency, such as a broad band produced by a short THz pulse. Theemission of the radiation set 150 can have multiple peaks, frequencyaspects that do not significantly impact the measured response, and/oraspects that introduce unwanted features to the measured response (e.g.,noise).

The radiation set 130 can be a plasmon emission that comprises one ormore frequencies. In one example, the emission component 110 emits afirst frequency at 0.2 terahertz and a second frequency at 0.6terahertz. The values of the first frequency and the second frequencycan be above (including equal to) about 0.2 terahertz and below(including equal to) about 40 terahertz. The emission component 110 canemit the first frequency and the reception component 120 can collect theresponse 150 from this emission. After the emission component 110 emitsthe first frequency, the emission component 110 can emit the secondfrequency such that the first frequency and second frequency are emittedin series and therefore frequencies of the radiation set 130 do notinterfere with one another.

The radiation set 130 can be a beam set upon an area of severalintegrated circuits 140 forming a system and the response 150 can becompared with responses of identical and fully functional integratedcircuits (e.g., etalon responses). With this, an impinging radiationbeam can be scanned over the area of the integrated circuits andmultiple responses can be recorded as a function of scanning beamposition with comparisons of the etalon responses (e.g., at the samescanning beam position). In one example, the radiation set 130 can bemodulated as a function of time or frequency and the response 150 can berecorded as a function of frequency or modulation frequency. Further, atemperature of the integrated circuit 140 can be modulated as a functionof time and the response 150 can be recorded as a function oftemperature and/or the modulation frequency. In one example, themodulation frequency of radiation can be between 1 Hz and 1 THz while amodulation frequency of temperature can be between 1 Hz and 1 MHz. Inone embodiment, the radiation set 130 is used to measure a low frequencynoise spectral density (e.g., that is the response 150) and thecomparison can be with an etalon noise spectral density, such as whenthe noise is measured in the bandwidth between 0.01 Hz and 10 MHz. Theradiation set 130 can be a radiation pattern.

The response 150 of the integrated circuit 140 to the radiation set 130can be a voltage. In one example, a transistor set of the integratedcircuit 140 can be biased with a substrate of the integrated circuit140. The radiation set 130 can cause the transistor set of theintegrated circuit 140 to respond by producing voltage due to thisbiasing. The reception component 120 can be physically coupled to a pinset of the integrated circuit 140. By way of this physical coupling tothe pin set, the reception component 120 can sense the voltage that isthe response 150 to the radiation set 130.

In one embodiment, the emission of the radiation set 130 upon theintegrated circuit 140 occurs wirelessly. In another embodiment, theemission component 110 can physically couple to the integrated circuit140 and the emission component 110 can emit the radiation set 130 by wayof a waveform generator. The integrated circuit 140 can comprise thetransistor set, such as a transistor set of at least about 1000transistors and therefore be considered a very large-scale integratedcircuit. The integrated circuit 140 can be packaged or unpackaged, beunder bias or unbiased, as well as being independent or installed in asystem.

The emission component 110 and the reception component 120 can beconsidered a system to test the integrated circuit 140 under bias bymeasuring the response 150 to the radiation set 130. The radiation set130 can be, for example, a radio frequency (about three gigahertz toabout three-hundred gigahertz), a sub-terahertz frequency (over aboutthree-hundred gigahertz to under about one terahertz), or terahertzfrequency (above about one terahertz). The response 150 can be betweenpins of the integrated circuit 140 when the integrated circuit 140 isilluminated by the radiation set 130. The response 150 can be, forexample, a function of frequency, radiation intensity, position of ascanning radiation beam on a surface of the integrated circuit 140, or acombination thereof.

In one example, the integrated circuit 140 can be silicon and underbias. The integrated circuit 140 can comprise a transistor set of fieldeffect transistors. The response 150 of the integrated circuit 140 tothe radiation set 130 can be by way of an excited decaying plasma wave.Example detection of the response 150 from the integrated circuit 140can comprises gate leakage current measurement, parasitic resistancemeasurement, channel mobility measurement, channel saturation velocitymeasurement, channel transport measurement, threshold voltagemeasurement, or a combination thereof.

In one embodiment, the system 100 can function for period and/orconstant monitoring of the integrated circuit 140. As part of this, thesystem 100 can comprise a component that transmits a visual and/or audiosignal indicating a failure or potential failure of the integratedcircuit 140. Additional fail safes can be implemented, such as shuttingdown an operation of a system that include the integrated circuit 140when the failure is detected or switching to another system that is notindicated as having a failure on its integrated circuit 140.

In one example, before beginning operation, multiple integrated circuits140 can be available. The emission component 110 and the receptioncomponent 120 can function upon the individual integrated circuits 140(e.g., each integrated into identical systems). A best performingintegrated circuit 140 (e.g., an integrated circuit 140 with fewestfailures) can be chosen. In one example, the reception component 120determines a placement of the individual integrated circuits 140 withina accuracy range (e.g., 1% to 100%), and chooses a highest placingintegrated circuit for initial usage.

FIG. 2 illustrates one embodiment of an environment 200 with a systemcomprising the emission component 110, the reception component 120, aselection component 210, and an evaluation component 220. The selectioncomponent 210 can be configured to select a radiation value for theradiation set 130 from a set of possible radiation values. Theevaluation component 220 can be configured to evaluate a feature set ofthe integrated circuit 140 to produce an evaluation result. Theselection of the radiation value can be based, at least in part, on theevaluation result.

In one example, physical characteristics for the integrated circuit 140can be inputted into a graphical user interface. These physicalcharacteristics can be an example of the feature set. Based on thesephysical characteristics, the selection component 210 can select theradiation value. One type of integrated circuit can have little responseto low frequencies, such as a frequency of about 0.2 terahertz, andtherefore low frequencies can be skipped and testing can occur at ahigher frequency. Conversely, the integrated circuit 140 can be highlydelicate. Therefore, subjecting the integrated circuit 140 to highfrequencies, such as a frequency of about 40 terahertz, can cause damageto the integrated circuit 140. Therefore, the selection component 210can select a frequency that is not anticipated to cause damage (unlesscausing such damage is desired).

FIG. 3 illustrates one embodiment of a system 300 comprising an analysiscomponent 310 and a determination component 320. The analysis component310 can be configured to perform an analysis on the response 150, suchas when the response 150 is produced by an emission of a radiation,which can be at least part of the radiation set 130 of FIG. 1, upon theintegrated circuit 140. The determination component 320 can beconfigured to determine a health of the integrated circuit 140 based, atleast in part, on a result of the analysis.

In one embodiment, the analysis can be voltage-based. The response 150can be a voltage. The analysis can comprise comparing the voltageagainst a voltage standard (e.g., a voltage from an etalon circuitconsidered a fully operational circuit). With this, a radiation emittedupon the integrated circuit 140 can be known and therefore an expectedresponse from the integrated circuit 140 can be known. The expectedresponse can be particular to a specific radiation. This expectedresponse can be the voltage standard. If the response does not match theexpected response, such as match within a defined tolerance, then thedetermination can be that the integrated circuit 140 is failing and nothealthy. Therefore, the determination component 320 can determine thehealth based, at least in part on if the comparison results such thatthe voltage meets the voltage standard. In this, the determinationcomponent 320 can establish from a difference that results from thecomparison the present or absence of one or more failures of theintegrated circuit and/or the nature of such failure(s).

This voltage-based analysis can function on a pin-by-pin level. In oneexample, the integrated circuit 140 can comprise thirty-two pins. Theindividual pins can have expected voltage responses of different valuesfrom one another. Thirty-one pins can have expected responses while onepin can have a voltage that does not meet the expected response. Thiscan be considered as the integrated circuit 140 failing since one pindoes not meet the expected response. However, a configuration can beused where one pin not meeting the expected response does not place thehealth of the integrated circuit 140 as failing.

As part of the voltage-based analysis, the determination component 320can determine health based on power supplied. The radiation set 130 ofFIG. 1 can be supplied at a certain power and based on this power avoltage can be expected as an expected response. The voltage can becompared against a power supplied, such as by an expected voltage basedon the power supplied, to determine the health of the integrated circuit140.

FIG. 4 illustrates one embodiment of a system 400 comprising theanalysis component 310, the determination component 320, and anidentification component 410. The identification component 410 can beconfigured to identify a failure in the integrated circuit 140 when thehealth of the circuit is determined to be failing. The failure can beidentified, at least in part, by way of a comparison discussed in FIG.3, such as based on a value of the voltage in comparison to an expectedvoltage.

Returning to the example above, the integrated circuit 140 can havethirty-two pins. Thirty-one of these pins can return an expected voltagewhile one pin can return with an unexpected voltage. While thedetermination component 320 can output a report of the failure, such asthat the integrated circuit 140 fails or highlight the pin that fails,the identification component 410 can identify the failure itself.

In one example, a higher than expected voltage can indicate a firstfailure while a lower than expected voltage can indicate a secondfailure. The first failure can be a physical failure of one hardwareportion of the integrated circuit 140 while the second failure can be aphysical failure of another, different hardware portion. In one example,the integrated circuit 140 is a Monolithic Microwave Integrated Circuit.

FIG. 5 illustrates one embodiment of a system 500 comprising a processor510 (e.g., a general purpose processor or a processor specificallydesigned for performing a functionality disclosed herein) and acomputer-readable medium 520 (e.g., non-transitory computer-readablemedium). In one embodiment, the computer-readable medium 520 iscommunicatively coupled to the processor 510 and stores a command setexecutable by the processor 510 to facilitate operation of at least onecomponent disclosed herein (e.g., the emission component 110 of FIG. 1).In one embodiment, at least one component disclosed herein (e.g., theanalysis component 310 of FIG. 3) can be implemented, at least in part,by way of non-software, such as implemented as hardware by way of thesystem 500. In one embodiment, the system 500 functions as the dataprocessing unit discussed in above regarding FIG. 1. In one embodiment,the computer-readable medium 520 is configured to storeprocessor-executable instructions that when executed by the processor510, cause the processor 510 to perform a method disclosed herein (e.g.,the methods 600-900 addressed below).

FIG. 6 illustrates one embodiment of a method 600 comprising threeactions 610-630. At 610, recognizing a failure of the integrated circuit140 of FIG. 1 can occur. This recognition can include determining thatthe failure exists, such as a yes/no determination, as well asidentifying the failure, such as an associated failing pin, portion, orhardware element (e.g., a specific transistor). This can be done by wayof a failure test apparatus (e.g., the system 100 of FIG. 1), such as byreceiving and processing a response from the failure test apparatus orbeing the failure test apparatus itself. At 620, determining a radiationfrequency (e.g., of the radiation set 130 of FIG. 1) subjected upon theintegrated circuit 140 of FIG. 1 can take place. Also at 620,determining a response voltage of the integrated circuit 140 of FIG. 1that is in response to being subjected to the radiation frequency cantake place. At 630, there can be propagating an information set onto adatabase, where the information set reflects the radiation, the responsevoltage, and the failure.

The database can be built or updated by way of this propagation. In oneexample, a customer can purchase a large number of integratedcircuits—this purchase can include multiple orders at different times todifferent physical locations. As information is learned about theintegrated circuits, this information can be aggregated into thedatabase. Users at different physical locations can use the database todiagnose, and potentially correct, failures. Additionally, informationin the database can be forwarded to an integrated circuit manufacturerso that their product can be improved and/or aspects disclosed hereincan be used by the integrated circuit manufacturer for quality controlpurposes.

FIG. 7 illustrates one embodiment of the action 610 illustrated as amethod comprising three actions 710-730. At 710, wirelessly emitting theradiation set 130 of FIG. 1 (e.g., one or more radio frequencies) uponthe integrated circuit 140 of FIG. 1 can occur. At 720, reading avoltage response of the integrated circuit 140 of FIG. 1 to theradiation set 130 of FIG. 1 can take place. The reading of the voltageresponse can occur by way of a physical coupling with a pin set of theintegrated circuit 140 of FIG. 1. At 730, there can be comparing anexpected voltage response to the radiation set 130 of FIG. 1 against thevoltage response to produce a comparison result. This comparison resultcan indicate the failure. In one example, the comparison can besubtracting the expected response from the voltage response and if theoutcome of the subtraction is not zero, within a tolerance, then afailure is indicated.

FIG. 8 illustrates one embodiment of a method 800 comprising six actions810-860. The method 800 can relate to a process of subjecting theintegrated circuit 140 of FIG. 1 to multiple frequencies (e.g., multipleradio waves at different radio frequencies in series). At 810, aradiation can be selected, such as 2 terahertz and, at 820, the 2terahertz radiation can be emitted. A response from the integratedcircuit 140 of FIG. 1 to this radiation can be received at 830 andanalyzed at 840. At 850, a check can occur to determine if theintegrated circuit 140 of FIG. 1 fails. If the integrated circuit 140 ofFIG. 1 does not fail, then the method 800 can return to action 810 andanother radiation can be selected, such as 4 terahertz. Otherembodiments can be practiced such as performing another check todetermine if another radiation should be selected, generating andoutputting a report that indicates the health of the integrated circuit140 of FIG. 1 (e.g., lighting a pass or a fail indicator light), ormaking an entry into a database. If the check at 850 indicates afailure, then the method can continue to, at 860, process the failure.An example of processing the failure can include generating andoutputting a report that indicates the failure.

The method 800 can end after processing the failure. In one example, afirst radiation and a second radiation (e.g., the first being higherthan the second) can be scheduled to be emitted. The first radiation canultimately cause a determination that the integrated circuit 140 of FIG.1 is failing. With this information, it can be unnecessary to subjectthe integrated circuit 140 of FIG. 1 to the second frequency if afailing end result is denoted by failure in light of a single radiofrequency. With this, resources can be saved such that emission does notoccur when failure is already identified.

FIG. 9 illustrates one embodiment of a method 900 comprising six actions810-840 and 910-920. The method 900 can function similarly to the method800 of FIG. 8 with actions 810-840 occurring, but here action 810 can beselecting the radiation set 130 of FIG. 1 (e.g., select the values offrequencies when more than one radiation frequency is selected). A checkcan be performed, at 910, on if another radiation should be emitted (orselected if the method 900 were to return to 810 instead of 820 asillustrated). If another frequency is to be emitted, then the method 900can return to action 820. If another frequency is not to be emitted,then, at 920, a report can be generated and outputted that indicates ahealth of the integrated circuit 140 of FIG. 1.

While aspects disclosed herein relate to a clear pass/fail evaluation ofthe integrated circuit 140 of FIG. 1, other implementations can bepracticed. In one example, the integrated circuit 140 of FIG. 1 can beexposed to first and second frequencies in accordance with the method900. A near perfect match can be considered a pass, a close match (e.g.,designated by a technician) can be a semi-pass, and a non-close andnon-near perfect match can be a fail. One of the two frequenciesresulting in a semi-pass and the other being a pass can be an overallpass. However, two frequencies resulting in a semi-pass can beconsidered a fail. With this, overall health is not determined until abattery is completed or until a failing threshold is met (e.g., one failor two semi-passes).

While the methods disclosed herein are shown and described as a seriesof blocks, it is to be appreciated by one of ordinary skill in the artthat the methods are not restricted by the order of the blocks, as someblocks can take place in different orders. Similarly, a block canoperate concurrently with at least one other block.

FIGS. 10A-10E illustrate one embodiment of a testing environment 1000Aand four graphs 1000B-E. FIG. 10A illustrates an example semiconductorand with low noise amplifiers operating in the frequency Range: 76-83GHz and 72-80 GHz, respectively. FIGS. 10B and 10C illustrate currentvoltage characteristics measured on the MMICs terminals which lead togates and drains of separate transistors in the semiconductor. Biasingand matching passive elements are included between these outputterminals and transistors. The graph 1000B shows the characteristics forthe virgin circuit while the graph 1000C shows the characteristics forthe circuit damaged by adding a drop of a conducting glue in thevicinity of the input transistor (Transistor 1 (T1)). The purpose ofthis conducting glue is to simulate an unintended short circuit, which,in practice, may result from a fault in the integrated-circuitfabrication process (for instance, during the metallization, sputtering,or annealing procedures).

FIGS. 10D and 10E illustrate the DC response on the drain terminals ofthe virgin 1000D and damaged 1000E amplifiers as a function of the gatevoltage under exposure to a low power 300 GHz radiation. Thesedependences have the similar shape as response from a single transistor.The response peaks at the transistor threshold voltage (as compared withgraphs 1000B and 100C). This shows that the THz response could be usedfor the threshold voltage extraction.

As can be seen, the two circuits have different shapes and amplitudes ofthe response. The shape of the dependences is in qualitative agreementwith the analytical theory of the overdamped plasmonic detection. Asseen from FIG. 10D, the response to 300 GHz radiation for thetransistors 1 and 2 is different, although their transfer currentvoltage characteristics are about identical. This is the effect ofinductors and capacitors as well as resistors included in the circuitfor the biasing and matching purposes.

In one embodiment, polarization dependences of the response comparedwith the cosine response can be as expected for a straight interconnectconductor. This shape of the polarization response is consistent withTHz radiation coupling via bonding connections. The polarizationresponse could be also used as a part of the test vector for identifyingthe circuit faults.

Aspects disclosed herein can be used for frequency dependence of theresponse as a part of the defect signature. The responsivity of FETs isa strong function of frequency and the device feature size. A crudeestimate of the peak response frequency, fpeak, can be given by fpeak,˜α/L, where L is the gate length and α ˜15 THz/nm, α ˜130 THz/nm, and α˜45 THz/nm for Si, InGaAs and GaN FETs, respectively. At lowerfrequencies, the response can drop approximately as 1/f² and, atfrequencies higher than the peak frequency it drops approximately as1/f^(0.5). Hence, this technique could work in fairly broad frequencyrange.

Practicing aspects disclosed herein can be used in resolving a singletransistor defect in an integrated circuit. The ultimate resolution canbe even higher, since the transistor response strongly depends on theboundary conditions at the gate edges, on the leakage current, and onparasitic resistances. A response to the THz radiation measured betweenthe pins or contact pads of an integrated circuit allows to establishand identify the integrated circuit faults using the response bias andpolarization dependences. This allows for the ability to identifyindividual transistor defects.

What is claimed is:
 1. A system, comprising: an evaluation componentconfigured to evaluate a feature set of an integrated circuit to producean evaluation result; a selection component configured to select aradiation value for a radiation set from a first possible radiationvalue and a second possible radiation value, where the selection of theradiation value is based, at least in part, on the evaluation result; anemission component configured to cause an emission of the radiation setupon the integrated circuit such that the integrated circuit produces aresponse; and a reception component configured to receive the response.2. The system of claim 1, where the radiation set comprises a firstfrequency and a second frequency, where the first frequency is differentfrom the second frequency, where the emission component causes anemission of the first frequency in series with an emission of the secondfrequency.
 3. The system of claim 1, where the radiation set ismodulated as a function of time.
 4. The system of claim 1, where theemission of the radiation set comprises a first emission at a firstradiation, where the emission of the radiation set comprises a secondemission at a second radiation, and where the first radiation and thesecond radiation are different radio frequencies.
 5. The system of claim1, where the response is a response by a transistor set of theintegrated circuit due to a bias of the transistor set.
 6. The system ofclaim 1, where the emission of the radiation set upon the integratedcircuit occurs wirelessly and where the reception component isconfigured to receive the response by way of physical coupling with thisintegrated circuit.
 7. The system of claim 1, where the integratedcircuit is incorporated into an apparatus when the integrated circuitproduces the response.
 8. A system, comprising: an emission componentconfigured to cause an emission of a radiation set upon an integratedcircuit such that the integrated circuit produces a response; and areception component configured to receive the response, where theresponse is a noise spectral density, where the response, in view of theradiation set, indicates a failure state of the integrated circuit andwhere the emission component, the reception component, or a combinationthereof is, at least in part, non-software.
 9. The system of claim 8,where the radiation set comprises a first frequency and a secondfrequency, where the first frequency is different from the secondfrequency, where the emission component causes an emission of the firstfrequency in series with an emission of the second frequency.
 10. Thesystem of claim 8, where the radiation set is modulated as a function oftime.
 11. The system of claim 8, where the reception component receivesthe response by way of a physical coupling to a pin set of theintegrated circuit.
 12. The system of claim 8, where the emission of theradiation set comprises a first emission at a first radiation, where theemission of the radiation set comprises a second emission at a secondradiation, and where the first radiation and the second radiation aredifferent radio frequencies.
 13. The system of claim 8, where theemission of the radiation set upon the integrated circuit occurswirelessly and where the reception component is configured to receivethe response by way of physical coupling with this integrated circuit.14. The system of claim 8, where the integrated circuit is incorporatedinto an apparatus when the integrated circuit produces the response. 15.A system, comprising: an emission component configured to cause anemission of a radiation set upon an integrated circuit such that theintegrated circuit produces a response; and a reception componentconfigured to receive the response, where the reception componentreceives the response as a voltage, where the reception componentreceives the response by way of a physical coupling to a pin set of theintegrated circuit, where the response, in view of the radiation set,indicates a failure state of the integrated circuit and where theemission component, the reception component, or a combination thereofis, at least in part, non-software.
 16. The system of claim 15, wherethe radiation set is modulated as a function of time.
 17. The system ofclaim 15, where the emission of the radiation set comprises a firstemission at a first radiation, where the emission of the radiation setcomprises a second emission at a second radiation, and where the firstradiation and the second radiation are different radio frequencies. 18.The system of claim 15, where the response is a response by a transistorset of the integrated circuit due to a bias of the transistor set. 19.The system of claim 15, where the emission of the radiation set upon theintegrated circuit occurs wirelessly and where the reception componentis configured to receive the response by way of physical coupling withthis integrated circuit.
 20. The system of claim 15, where theintegrated circuit is incorporated into an apparatus when the integratedcircuit produces the response.